875 liters equals how many kilograms?

Answer 1

It doesn't. A litre is a measurement for volume, a kilogram is a measurement for mass. To determine the mass of a particular volume, we need to know the density of the material in question.
m = ρ * V
(mass = density * volume)

For instance, the density of water is usually 1 kg / l, so the mass of 875 litres would be 875 kilograms.
Density of Mercury is around 13.5 kg / l, so the mass would be 11407 kg.

Answer 2

To convert liters to kilograms, you need to know the density of the substance. Without this information, the conversion is not possible as liters and kilograms measure different properties (volume and mass).